Rolling Shutter Barcode Scanner Illumination Control
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Solution Overview
Problem
Traditional barcode imaging systems require multiple image frames to set proper exposure and illumination power, leading to prolonged processing times for successful barcode decoding.
Innovation Solution
A barcode imaging engine with an illumination system that varies output power during image acquisition, utilizing rolling shutter mode to capture a single image with increasing illumination settings across rows, allowing for rapid determination of optimal exposure and illumination power settings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional barcode imaging systems use multiple image frames to set proper exposure and illumination power, then the barcode decoding accuracy is improved, but the processing time is prolonged
Solution Approach 1:
The image sensor array is divided into multiple rows, each capturing image data at different illumination power levels within a single frame. This segmentation allows the system to obtain multiple exposure levels simultaneously rather than sequentially, resolving the contradiction between decoding accuracy (needing multiple exposure levels) and processing time (requiring multiple frames).
Solution Approach 2:
The patent adds the dimension of spatial variation across rows to the illumination power parameter. Instead of varying illumination over time (temporal dimension) through multiple frames, the system varies illumination across different rows (spatial dimension) within a single frame, enabling simultaneous capture of multiple exposure levels without increasing processing time.
2Reliability
If multiple image frames are captured to determine optimal exposure settings, then the barcode reading reliability is improved, but the productivity is reduced
Solution Approach 1:
The sensor array rows are segmented to capture different illumination levels simultaneously, allowing the system to maintain high reading reliability through multiple exposure samples while capturing all data in a single frame, thus improving productivity by eliminating the need for sequential frame capture.
Solution Approach 2:
The patent merges multiple exposure level captures that would traditionally require separate frames into a single frame by assigning different rows to different illumination power levels. This combining approach maintains the reliability benefits of multiple exposure samples while achieving the productivity improvement of single-frame operation.
3Measurement precision
If the illumination power is varied during image acquisition, then the exposure setting accuracy is improved, but the device complexity increases
Solution Approach 1:
The system uses the inherent row-sequential reading capability of rolling shutter sensors to automatically assign different illumination power levels to different rows without requiring additional complex control mechanisms. Each row self-services by capturing data at its assigned illumination level, simplifying the overall device complexity while maintaining exposure accuracy.
Solution Approach 2:
The patent makes the single image sensor array perform multiple functions by having different rows capture data at different illumination levels simultaneously. This multi-functionality allows the system to achieve accurate exposure settings without adding separate sensors or complex illumination control systems, thereby avoiding increased device complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables quick identification of proper exposure and illumination settings for successful barcode decoding in a single image acquisition, reducing the need for multiple frames and significantly shortening the decoding process.
Implementation Method 1
detecting light returned from a target object through an imaging lens arrangement with an imaging sensor during a first frame exposure time period
Implementation Method 2
when a first illumination light is projected towards the target object; when a second illumination light is projected towards the target object
Data Source
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AI summary
A method includes the following (1) detecting light returned from a target with an imaging sensor during a first frame exposure time period to capture a first image when a first illumination light is projected towards the target; (2) processing the first image to determine the light intensity of a second illumination light; (3) detecting light returned from the target with the imaging sensor during a second frame exposure time period to capture a second image when the second illumination light is projected towards the target; and (4) decoding a barcode in the second image. The light intensity of the first illumination light changes with time at least during part of the first frame exposure time period.